Nitrocellulose has long been used as a base film forming material for various films and coatings. One of its many applications is in lacquer emulsions used in the manufacture of nail coatings or polishes.
Nitrocellulose emulsions used in coatings are generally obtained through either direct emulsification or indirectly through various inversion techniques. For example, a conventional lacquer of nitrocellulose and solvent with emulsifiers is emulsified with the addition of water, inverting from a water-in-lacquer to a lacquer-in-water emulsion. Another inversion technique begins with water-wet nitrocellulose which is dissolved in the solvent system, with water from the mixture dispersing throughout the solvent phase. Additional water containing an emulsifying agent is added forming a lacquer-in-water emulsion by inversion.
Although many improvements have been made in nail coating performance, conventional nail coatings still employ a relatively high percentage of volatile water-immiscible solvents which are relatively toxic, in order to emulsify the nitrocellulose based material. Water-miscible solvents are not ordinarily used because they promote formation of water-in-lacquer rather than lacquer-in-water emulsions. Due to the high percentage of water-immiscible solvents ordinarily employed to emulsify the nitrocellulose, the resultant coatings are flammable and potentially toxic, with a high rate of volatilization and an unpleasant odor. In addition, some individuals become sensitized and develop reactions to these nail coatings.
It is therefore desirable to provide a method for emulsifying nitrocellulose with less reliance on a high percentage of harsh solvents. It is also desirable to provide nitrocellulose-based compositions which have reduced environmental impact by employing a greater percentage of water. It is further desirable to provide nitrocellulose-based compositions for coatings with a lower percentage of solvent. It is further desirable to provide improved nail coatings with a lower percentage of solvents, but which do not sacrifice durability and hardness characteristics.